Machine Tool

ABSTRACT

In order to improve a machine tool for machining a workpiece by a relative movement between the workpiece and a tool, comprising a first receiving device for the workpiece or the tool, a compound slide system with a second receiving device for the tool or the workpiece and comprising a drive device for moving the second receiving device in relation to the first receiving device, which drive device acts at least two spaced-apart points of application by at least three drive struts extending parallel to at least two different directions and each with a pivot joint, and with which drive device the at least two points of application can be positioned by means of the at least three drive struts, in such a way that exact positioning of the second slide element can be achieved by structural measures, it is proposed that four drive struts of invariant length, each with a pivot joint, act on the slide element, each of which struts is pivotally connected to a guiding slide, which is guided in a linearly movable manner transversely in relation to the longitudinal direction of the respective drive struts, and a maximum of two of which drive struts run parallel to one another.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is a continuation of co-pending U.S. patentapplication Ser. No. 11/508,573, filed Aug. 23, 2006, and claims thebenefit of German Application No. 10 2005 041 496.6, filed Sep. 1, 2005,the teachings and disclosure of which are hereby incorporated in itsentirety by reference thereto.

BACKGROUND OF THE INVENTION

The invention relates to a machine tool for machining a workpiece by arelative movement between the workpiece and a tool, comprising a machineframe, a carrier disposed on the machine frame and having a firstreceiving means for the workpiece or tool, a compound slide systemdisposed on the machine frame and having a slide element which carries asecond receiving means for the tool or the workpiece and can be moved bythe compound slide system in relation to the first receiving means in afixed movement zone of a compound slide movement area in the directionof two compound slide movement axes running transversely in relation toone another and comprising a drive device for moving the slide elementthat is movable in relation to the first receiving means, which drivedevice acts on the slide element at least two spaced-apart points ofapplication by at least three drive struts extending parallel to atleast two different directions and each with a pivot joint, and withwhich drive device the at least two points of application can bepositioned by means of the at least three drive struts.

Machine tools of this type are already known from the prior art, forexample from DE 100 19 788 A1.

In the case of a machine tool of this type, it has been found that therequired precision in the positioning of the second slide elementrequires complex measuring systems.

It is therefore an object of the invention to achieve exact positioningof the second slide element by structural measures.

SUMMARY OF THE INVENTION

This object is achieved according to the invention in the case of amachine tool of the type described at the beginning by four drive strutsof invariant length, each with a pivot joint, acting on the slideelement, each of which struts is pivotally connected to a guiding slide,which is guided in a linearly movable manner transversely in relation tothe longitudinal direction of the respective drive struts, and a maximumof two of which struts run parallel to one another.

The advantage of the solution according to the invention is to be seenin the fact that the precision of the positioning of the second slideelement is distinctly improved by the four drive struts, in particularby an improvement of the torsional stiffness about axes of rotationrunning perpendicularly in relation to the compound slide movement area,in particular about a so-called B axis.

The second slide element can be positioned particularly advantageouslyif the four drive struts form two drive groups, each with twonon-parallel drive struts, so that the two drive groups can uniquely fixthe position of the movable slide element.

A particularly suitable solution provides here that a position of theslide element can be fixed with the first drive group apart from a firststill possible form of movement.

A further advantageous solution provides that a position of the slideelement can be fixed with the second drive group apart from a secondstill possible form of movement.

Since, however, the first drive group and the second drive group do notact at identical points of the movable slide element, a uniquepositioning of the movable slide element is thereby obtained, since thefirst still possible form of movement as a result of the first drivegroup is blocked by the second drive group and the second still possibleform of movement due to the second drive group is blocked by the firstdrive group.

In principle, the drive struts of each drive group act on the movableslide element with a point of application of their own, so that fourdrive struts may be provided altogether, each acting on the slideelement with their own points of application.

To improve the stability of the positioning, however, it has proven tobe advantageous if the drive struts of one of the drive groups act onthe movable slide element at a common point of application.

In this case, the respective still possible form of movement of theslide element represents a pivoting movement about the common point ofapplication.

However, it is even more advantageous for the precision of thepositioning of the slide element if the drive struts of each of thedrive groups respectively act on the slide element at one of twospaced-apart points of application.

In this case, consequently, only two points of application are providedon the slide element, each of which is uniquely and stably defined bythe respective drive group apart from the still free possible form ofmovement in the form of a pivoting movement.

With regard to the path followed by the guiding directions of theguiding slides, nothing has been stated in connection with thedescription so far of the solution according to the invention. Forexample, it is conceivable for two guiding slides to be movably disposedin each case, parallel to the same guiding direction. This could be, forexample, the guiding slides respectively of one drive group, in whichcase the guiding directions of the two drive groups could still differfrom one another.

However, in order to minimize the space required for the drive device,it is advantageous if in each case two of the guiding slides are guidedon a common guideway.

In this case, there is the possibility of for example allowing theguiding slides of each drive group to run on a common guideway.

A further advantageous solution provides that the guiding slides of thedrive struts are guided in guiding directions running parallel to oneanother.

There is consequently the possibility in principle of guiding each ofthe guiding slides along a guiding direction of its own, whichdirections however all run parallel to one another.

It is particularly advantageous, however, if a first guiding slide ofthe first drive group and a first guiding slide of the second drivegroup are movable along the same guiding direction.

Such a solution is still more space-saving if the first guiding slidesof the first and second drive groups are guided on a common guideway.

Furthermore, an advantageous exemplary embodiment provides that a secondguiding slide of the first drive group and a second guiding slide of thesecond drive group are movable along the same guiding direction.

Furthermore, it is advantageous if a second guiding slide of the firstdrive group and a second guiding slide of the second drive group areguided on a common guideway.

In order to simplify the drive of the guiding slides, a particularlyadvantageous solution provides that the first guiding slides of thefirst and second drive groups are rigidly coupled to one another, thatis to say that the first guiding slides of the first and second drivegroups are only movable together with one another.

A rigid coupling of the first guiding slides to one another in this waymay take place for example by a rigid coupling of the drives of thefirst two guiding slides taking place via the control.

The rigid coupling can be realized particularly easily if the firstguiding slides of the first and second drive groups are rigidly coupledto one another mechanically.

As an alternative to this, however, it is also conceivable to combinethe first guiding slides of the first and second drive groups to form acommon guiding slide.

Furthermore, it is provided in a similar way that the second guidingslides of the first and second drive groups are rigidly coupled to oneanother, so that they can also be driven in a simple manner.

In this case it would likewise be conceivable to provide a rigidcoupling of the second guiding slides via a control for the drives ofthe two second guiding slides, it being easier for the rigid coupling tobe realized if the second guiding slides of the first and second drivegroups are rigidly coupled to one another mechanically.

A solution that is spatially particularly advantageous and of a smallconstruction provides that all the guiding slides are disposed on acommon guideway.

When all the guiding slides are provided on a common guideway, theguiding slides are preferably disposed one following the other on it.

It is particularly advantageous in this case if the guiding slides ofeach drive group are disposed one directly following the other, thisdirectly successive sequence in which the guiding slides are disposedproviding within the scope of the solution according to the invention acontrollable variable spacing between the guiding slides in addition tothe controllable variable position along the guiding direction.

A mechanical coupling of the first guiding slides of the drive groupsand the second guiding slides of the drive groups can be realizedparticularly advantageously when all the guiding slides are provided ona common guideway, if the mechanically rigid connection between thefirst guiding slides runs on a different side of the guideway than themechanically rigid connection between the second guiding slides.

The kinematics of the drive device according to the invention can berealized particularly easily if two of the drive struts respectively runparallel to one another.

It is preferably provided in this case that the drive struts articulatedon the first guiding slides of the drive groups run parallel to oneanother and the drive struts articulated on the second guiding slides ofthe drive groups run parallel to one another.

Furthermore, the kinematics according to the invention can be controlledparticularly easily if two of the four drive struts respectively are ofthe same length.

The drive struts are preferably designed in such a way that all fourdrive struts are of the same length.

With regard to the drive of the guiding slides, it would be conceivablein principle to drive each of the guiding slides separately.

In particular in the case where the first guiding slides of the drivegroups and the second guiding slides of the drive groups, respectively,are rigidly coupled to one another, it is adequate if a linear drive isassociated with the respectively mechanically coupled guiding slides.

The linear drive could be, for example, a linear motor. However, it ismechanically simpler if the linear drive is a spindle drive.

With regard to the disposition of the guideways for the guiding slides,so far nothing more specific has been stated. So a structurallyparticularly advantageous solution provides that all the guideways forall the guiding slides are disposed on the same side of the points ofapplication, in order to make the drive device according to theinvention as compact as possible.

In order to allow the relative position, and consequently in particularthe position in the X direction, to be easily detected, a measuringsystem which directly detects a relative position of the first guidingslides in relation to the second guiding slides is provided.

Position detection of this kind can be realized particularlyadvantageously if the measuring system is disposed on connecting strutsof the first guiding slides and of the second guiding slides.

As an alternative or in addition to the solution described so far, afurther solution provides that drive struts of invariant length act onthe slide element, each of which struts is pivotally connected to aguiding slide, which is guided in a linearly movable manner transverselyin relation to the longitudinal direction of the drive struts, and thatguideways for at least two of the guiding slides are disposed on a sideof the points of application facing the spindle axis.

The advantage of this solution can be seen in that the drive strutsconsequently extend from a region of the machine tool which undergoesminor thermal displacements with respect to the spindle axis, andconsequently also the position of the movable slide elements that ispredetermined by the drive device undergoes only minor thermaldisplacements.

Furthermore, it is advantageous in the case of this solution that, onaccount of their invariance of length, no heat directly enters the drivestruts as a result of a length adjustment of the same, so that thethermal displacement in the region of the drive struts can also be keptlow.

In the case of this solution, it is particularly advantageous if theguideways for the guiding slides are disposed near a reference planewhich runs through the spindle axis and perpendicularly in relation tothe X direction of the machine tool.

This solution has the great advantage that the base for the drive strutsof the drive device consequently already lies near the spindle axis, andconsequently substantially only thermal displacements in the region ofthe drive struts have any effect on the position of the movable slideelement, while all other thermal displacements, in particular in themachine bed body, have substantially no effect on the position of themovable slide element in relation to the spindle axis.

It is particularly advantageous if the guideways for all the guidingslides are disposed on the side of the points of application facing thespindle axis, so that all the drive struts have an effect on thepositioning accuracy in the same direction in the event of a thermallyinduced change in their length.

Otherwise, further advantageous embodiments have the same features asdescribed above.

Further features and advantages of the invention are the subject of thedescription which follows and of the graphic representation of anexemplary embodiment of a solution according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective schematic representation of an exemplaryembodiment of a machine tool looking toward a front side, but withoutshowing a slide element on the machine bed side for an upper movableslide element;

FIG. 2 shows a perspective representation of the machine tool looking atthe rear side;

FIG. 3 shows a perspective representation of the drive device as used inthe exemplary embodiment represented of the machine tool, and

FIG. 4 shows a section along line 4-4 in FIG. 3.

FIG. 5 shows a view similar to that of FIG. 3, but with the points ofapplication 82, 84 schematically shown affixed to a slide elementincluding receiving means for receiving a workpiece instead of a tool,in an embodiment wherein this slide element moves the workpiece relativeto receiving means for receiving a tool.

DETAILED DESCRIPTION OF THE INVENTION

An exemplary embodiment of a machine tool according to the invention,represented in FIG. 1, comprises a machine frame, which is designated asa whole by 10, can be placed with a foot 12 on a base area and comprisesa machine bed body, which is designated as a whole by 20 and ispreferably formed in a way similar to a plate.

On this machine bed body 20 there are, for example, two headstocks 22,24, in which workpiece spindles 30, 32 are disposed coaxially inrelation to a spindle axis 26, lie opposite each other and are providedwith workpiece receiving means 34, 36 for workpieces WS, which representfirst receiving means and are disposed facing one another.

In this case, the machine tool represents a lathe.

However, instead of workpiece spindles 30, 32, it would also beconceivable to provide tool spindles with tool receiving means.

In the case of this exemplary embodiment of the machine tool accordingto the invention, the headstock 22 is disposed on the machine bed body20 in a stationary manner, while the headstock 24 can for example bemade to move in the direction of the spindle axis 26.

However, it would also be conceivable to arrange for both headstocks 22,24 to be movable in relation to the machine bed body 20.

For machining the workpieces WS disposed in the workpiece receivingmeans 34, 36, a tool carrier 38, which can only be made to movetransversely in relation to the spindle axis 26 and is associated withthe workpiece spindle 32, and also tool carriers 40, 42, which areassociated with the workpiece spindles 30, 32, are provided, each ofwhich comprises a multiplicity of tool receiving means 44, 46 for toolsWZ, representing second receiving means.

In order to allow the tool carriers 40, 42, and consequently the toolreceiving means 44, 46, to be moved in relation to the workpiecereceiving means 34, 36, the tool carriers 40, 42 are disposed on forexample identically constructed compound slide systems 50, 52, each ofwhich comprises a first slide element 60 on the machine bed side, whichis formed for example as a plate 62 with an aperture 64 in a centralregion of the same and has around the aperture 64 surfaces 66, 68running substantially parallel to one another, the surfaces 66 beingfront surfaces and the surfaces 68 being rear surfaces of the plate 62.

As an alternative to this, instead of the plate 62, it is alsoconceivable to provide on both sides of the aperture 64 guiding strips,which lie with their two surfaces 66, 68 respectively in the same plane.

On this first slide element 60 on the machine bed side, a second slideelement 70 on the tool carrier side is movably guided, to be precise bythe latter sliding with guiding bodies 72, 74 on the surfaces 66, 68.

Consequently, the surfaces 66, 68 of the first slide element 60 runningparallel to one another define a compound slide movement area, parallelto which the respective second slide element 70 is movable in relationto the machine bed body 20, both in the X direction, that is to saytransversely in relation to the spindle axis 26, and in the Z direction,that is to say parallel to the spindle axis 26.

Further details and embodiments of compound slide systems 50, 52 of thistype, in which the respective second slide element 70 is movable in thedirection of both compound slide movement axes X, Z, are described inGerman Patent Application DE 100 19 788 A1, to which reference is madewith regard to the embodiments of the various compound slide systems.

The tool carriers 40, 42 are preferably also in each case rotatable withrespect to the corresponding second slide element 70 about a B axis,which is perpendicular to the X/Z plane.

For moving the respective second slide element 70 in relation to therespective first slide element 60, as represented in FIG. 2, associatedwith each compound slide system 50, 52 is a drive device 80, which actson the respective slide element 70 at two spaced-apart points ofapplication 82, 84, in order to position the respective second slideelement 70 in relation to the first slide element 60 in the X and Zdirections in the respective compound slide movement plane.

As shown enlarged in FIGS. 3 and 4, the drive device 80 comprisesaltogether four drive struts 90, 92, 94, 96, the drive struts 90 and 92acting by means of pivot joints 100, 102 at the point of application 82,formed by a bearing pin 86, and the drive struts 94 and 96 acting bymeans of pivot joints 104 and 106 on a bearing pin 88 defining the pointof application 84.

Furthermore, each of the drive struts 90, 92, 94, 96 is pivotallyconnected by means of a pivot joint 110, 112, 114, 116 to in each case aguiding slide 120, 122, 124, 126, the guiding slides 120, 122, 124, 126being guided along a guideway 132, which fixes a common guidingdirection 130 and is formed for example by a guiding rail 134.

The guiding rail 134 is preferably disposed on a rear side 136 of themachine bed body 20 and is held by the machine bed body 20.

Disposed in this way, the drive struts 90, 92, 94, 96 always extend withtheir longitudinal directions 140, 142, 144, 146 transversely, inparticular obliquely, in relation to the guiding direction 130,irrespective of the position of the guiding slides 120 to 126 along theguideway 132, and the longitudinal directions 140, 142, 144 and 146 runparallel to a central plane 154.

Furthermore, in the case of the exemplary embodiment represented, thedrive struts 90, 92, 94, 96 are formed in such a way that their lengthbetween the respective pivot joints 100 and 110, 102 and 112, 104 and114 and also 106 and 116 is of the same size.

In addition, the guiding slides 120 and 122 and also 124 and 126 arepositioned in relation to one another in such a way that thelongitudinal directions 140 and 144 of the drive struts 90 and 94 andalso the longitudinal directions 142 and 146 of the drive struts 92 and96 run parallel to one another.

This can be achieved in particular by the guiding slides 120 and 124being rigidly coupled to one another by connecting struts 150 and 152,the connecting struts 150 and 152 running between the guiding slides 120and 124, for example on both sides of the central plane 154 of the drivedevice 80, to be precise at such a spacing from the guiding slide 122that the latter can move freely between the connecting struts 150 and152 and also along the guideway 132 between the guiding slides 120 and124.

The connecting struts 150 and 152 in this case preferably lie in such away that they act on side faces 156 and 158 of the guiding slides 120and 124, the side faces 156 and 158 being side faces of the guidingslides 120 and 124 that run for example approximately parallel orobliquely in relation to the central plane 154.

Furthermore, the guiding slides 122 and 126 are likewise rigidly coupledto one another by connecting struts 160 and 162, the connecting struts162 and 164 acting on the guiding slides 122 and 126 in the region ofupper sides 166 and 168 running transversely in relation to the centralplane 154, and consequently running in a collision-free manner inrelation to the connecting struts 150 and 152, and the connecting struts160 and 162 being disposed with such a spacing from one another that apivot joint flange 174 of the guiding slide 124 is freely movablebetween the connecting struts 160 and 162.

Otherwise, all the pivot joint flanges 170, 172, 174 and 176 supportingthe pivot joints 110, 112, 114 and 116 are formed in such a way that thepivot joints 110, 112, 114 and 116 can be moved at the same spacing fromthe guiding rail 134 and parallel to the guiding direction 130 by movingthe guiding slides 120, 122, 124 and 126.

The parallel alignment of the longitudinal directions 140 and 144 of thedrive struts 90 and 94 and also of the longitudinal directions 142 and146 of the drive struts 92 and 96 is ensured in every relative positionof the guiding slides 120 and 124 with respect to the guiding slides 122and 126 by the rigid connection of the guiding slides 120 and 124 andalso 122 and 126 by means of the connecting struts 150 and 152 or 160and 162, respectively.

Consequently, the drive struts 90 and 92, the pivot joints 110 and 112of which are always spaced apart from one another while the pivot joints100 and 102 of which act on the same bearing pin 86, form the sides ofan isosceles triangle, which on the one hand uniquely fixes the positionof the point of application 82 in the guiding direction 130, whichpreferably runs parallel to the Z direction of the machine tool, and onthe other hand also uniquely fixes its spacing from the guideway 132,which corresponds to the X direction whenever—as provided in the case ofthe exemplary embodiment represented—the central plane 154 of the drivedevice 80 runs parallel to the compound slide movement plane, andconsequently parallel to the surfaces 66 and 68 of the first slideelement 60.

Consequently, the Z position of the point of application 82 on the slideelement 70 can be uniquely fixed by the absolute position of the guidingslides 120 and 122 in the guiding direction 130, and the X position ofthe point of application 82 on the slide element 70 can be uniquelyfixed by the relative position of the guiding slides 120 and 122.

The single degree of freedom of the movement of the slide element 70when the point of application 82 is fixed in such a way consists in theslide element 70 having the possibility of turning about the point ofapplication 82 on account of the pivot joints 100 and 102, and thebearing pins 86 that are consequently rotatable in relation to thelatter.

Altogether, the drive struts 90 and 92, the longitudinal directions 140and 142 of which run transversely in relation to one another, preferablyin a V-shaped manner with respect to the point of application 82,consequently form a drive group 180, which fixes the X and Z positionsof the point of application 82 of the slide element 70.

In the same way, the drive struts 94 and 96 form a drive group 182,since these drive struts 94 and 96 also form the sides of an isoscelestriangle and, on the basis of the spaced-apart pivot joints 114 and 116and the pivot joints 104 and 106, acting together on the bearing pin 88,uniquely define the point of application 84 in relation to the Zdirection and in relation to the X direction of the machine tool for thesame reasons as described in connection with the first drive group 180,so that the slide element 70 would only be left with the possibility ofrotating about the point of application 84.

However, the position of the slide element 70 with regard to itsposition in the X direction and the Z direction is likewise uniquelyfixed by the unique fixing of both points of application 82 and 84, andfurthermore this drive device 80 only allows the slide element 70 to bedisplaced in positions in which the slide element 70 always maintainsthe same alignment in relation to the Z direction and the X direction,which is evident from the fact that a connecting line 184 between thepoints of application 82 and 84 always remains aligned parallel to theguiding direction 130, irrespective of the position of the guidingslides 122 and 126 in relation to the guiding slides 120 and 124, sincethe drive struts 90 and 94 and also 92 and 96 also always remain alignedparallel to one another on account of the rigid mechanical coupling ofthe guiding slides 120 and 124 and also 122 and 126, and consequentlythere is double parallel guidance for the slide element 70.

As represented in FIG. 2, the movement of the guiding slides 120 and 124takes place by means of a first linear drive 190, which could be formedfor example as an electric linear motor, but is preferably a spindledrive, and comprises an adjusting spindle 192, on which there is aspindle nut 194, which is for example fixedly connected to the bearingflange 170 of the first guiding slide 120.

The adjusting spindle 192 is for its part mounted in a bearing support196 fixedly connected to the machine bed body 20 in such a way that itis non-displaceable in the direction of its longitudinal axis 198 butrotatable, so that turning of the adjusting spindle 192 leads to adisplacement of the spindle nut 194 in the direction of the longitudinalaxis 198.

Furthermore, the adjusting spindle 192 can be driven in a rotatingmanner about the longitudinal axis 198 by a drive 200.

Consequently, the guiding slides 120 and 124 can be moved together inthe guiding direction 130 by the linear drive 190.

In the same way, a second linear drive 210 is provided for moving theguiding slides 122 and 126, which drive comprises an adjusting spindle212, a spindle nut 214 and a bearing support 216, the adjusting spindle212 being accommodated in the bearing support 216 in such a way that itis immovable in the direction of its longitudinal axis 218 butrotatable.

Since it is also provided in the case of the second linear drive 210that the spindle nut 214 is fixedly connected to one of the guidingslides, in this case the guiding slide 126, both the guiding slide 126and the guiding slide 122 can be displaced in the guiding direction 130by turning the adjusting spindle 212, for example driven by a drive 220.

Depending on the absolute position of the guiding slides 120 and 124 or122 and 126, and depending on the relative position of the guidingslides 120 and 124 or 122 and 126, the position of the second slideelement 70 can consequently be fixed with the required rigidity both inthe Z direction and in the X direction.

The absolute position of the guiding slides 120 and 124 or 122 and 126can be detected in this case by rotary encoders which are associatedwith the linear drives 190 and 210 and detect the rotational positionsof the adjusting spindles 192 and 212.

Furthermore, as already represented in FIG. 3, the relative position ofthe guiding slides 120 and 124 or 122 and 126 that are connected to oneanother can be detected by a measuring system 230, which comprises afirst element 232, disposed for example on the connecting strut 150, anda second element 234, disposed on the connecting strut 160, so that thetwo elements 232 and 234 are displaceable with respect to one another,one of the elements carrying a glass scale, with which the relativeposition of the guiding slides 120 and 124 and also 122 and 126 that arecoupled to one another can be detected, this relative positionrepresenting a measure of the position of the second slide element 70 inthe X direction of the machine tool.

In order to minimize the effects of thermal displacements on theposition of the slide elements 70 ₁ and 70 ₂, the guiding rails 134 ofthe drive devices 80 are preferably disposed in such a way that they lieon a side of the points of application 82, 84 that is facing the spindleaxis 26, in particular near a reference plane 240 of the machine toolwhich runs through the spindle axis 26 and perpendicularly in relationto the X direction, that is to say parallel to the Y direction.Consequently, the thermal displacements caused by the drive devices 80according to the invention are minimal, in particular since the drivestruts 90, 92, 94, 96 do not have their own heat-dissipating drives, butinstead the heat-dissipating drives, namely the drives 200 and 220, canbe disposed at a sufficient distance from the drive device 80, so thatheat only enters the drive devices 80 ₁ and 80 ₂ according to theinvention indirectly via the drives 200, 220, and consequently theresultant thermal displacements are likewise minimal.

Furthermore, the guiding rail 134 associated with the respective drivedevice 80 ₁ and 80 ₂ is fixedly connected directly to the machine bedbody 20 near the reference plane 240, so that thermal displacements ofthe reference plane 240 itself, for example caused by heating of themachine bed body 20, do not have any effect on the positional accuracyof the respective second slide element 70 ₁ or 70 ₂, since its positionrelates substantially to the relative position in relation to thereference plane 240, the absolute position of which is immaterial.

The drives 200, 220 of each of the drive devices 80 ₁ and 80 ₂ can becontrolled by means of a control which is designated as a whole by 250,positions the respective slide element 70 in the X direction bysynchronous displacement of the guiding slides 120 and 124 or 122 and126 that are coupled to one another and converts the desired position ofthe slide element 70 in the X direction into a relative position betweenthe slide elements 120 and 124 or 122 and 126 that are coupled to oneanother.

1. Machine tool for machining a workpiece by a relative movement betweenthe workpiece and a tool, comprising a machine frame, a carrier disposedon the machine frame and having a first receiving means for theworkpiece or the tool, a compound slide system disposed on the machineframe and having a slide element which carries a second receiving meansfor the tool or the workpiece and can be moved by the compound slidesystem in relation to the first receiving means in a fixed movement zoneof a compound slide movement area in the direction of two compound slidemovement axes running transversely in relation to one another andcomprising a drive device for moving the slide element that is movablein relation to the first receiving means, which drive device acts on theslide element at least two spaced-apart points of application by fourdrive struts extending parallel to at least two different directions,and with which drive device the at least two points of application canbe positioned by means of the four drive struts, said four drive strutsbeing of invariant length, each with a pivot joint and acting on theslide element, each of which drive struts being pivotally connected to arespective guiding slide, which is guided in a linearly movable mannertransversely in relation to the longitudinal direction of the respectivedrive struts, and all guiding slides being guided on a common guideway.2. Machine tool according to claim 1, wherein the slide element isrotationally fixed.
 3. Machine tool according to claim 1, wherein theslide element can be linearly movable in at least one direction. 4.Machine tool according to claim 1, wherein the guiding slides of thefour drive struts are guided in guiding directions running parallel toone another.
 5. Machine tool according to claim 1, wherein the guidingslides are disposed one following the other on the guideway.
 6. Machinetool according to claim 1, wherein the four drive struts form two drivegroups, each with non-parallel drive struts, the guiding slides of eachdrive group are disposed one directly following the other.
 7. Machinetool according to claim 1, wherein a mechanically rigid connectionbetween the first guiding slides runs on a different side of theguideway than a mechanically rigid connection between second guidingslides of the first drive group and the second drive group.
 8. Machinetool according to claim 1, wherein two of the four drive strutsrespectively run parallel to one another.
 9. Machine tool according toclaim 1, wherein two of the four drive struts respectively are of thesame length.
 10. Machine tool according to claim 1, wherein all fourdrive struts are of the same length.
 11. Machine tool for machining aworkpiece by a relative movement between the workpiece and a tool,comprising a machine frame, a carrier disposed on the machine frame andhaving a first receiving means for the workpiece or the tool, a compoundslide system disposed on the machine frame and having a slide elementwhich carries a second receiving means for the tool or the workpiece andcan be moved by the compound slide system in relation to the firstreceiving means in a fixed movement zone of a compound slide movementarea in the direction of two compound slide movement axes runningtransversely in relation to one another and comprising a drive devicefor moving the slide element that is movable in relation to the firstreceiving means, which drive device acts on the slide element at leasttwo spaced-apart points of application by four drive struts extendingparallel to at least two different directions, and with which drivedevice the at least two points of application can be positioned by meansof the four drive struts, said four drive struts being of invariantlength, each with a pivot joint, act on the slide element, each of whichdrive struts being pivotally connected to a guiding slide, which isguided in a linearly movable manner transversely in relation to thelongitudinal direction of the respective drive struts, a maximum of twoof which drive struts running parallel to one another, the four drivestruts forming two drive groups, each with two non-parallel drivestruts, a first guiding slide of the first drive group and a first ofthe guiding slides of the second drive group are guided on a commonguideway.
 12. Machine tool according to claim 11, wherein the drivestruts of one of the drive groups act on the slide element at one of thecommon point of application.
 13. Machine tool according to claim 11,wherein the drive struts of each of the drive groups respectively act onthe slide element at one of two of the spaced-apart points ofapplication.
 14. Machine tool according to claim 11, wherein a second ofthe guiding slides of the first drive group and a second of the guidingslides of the second drive group are movable along the same guidingdirection.
 15. Machine tool according to claim 14, wherein the secondguiding slides of the first and second drive groups are guided on acommon guideway.
 16. Machine tool according to claim 11, wherein thefirst guiding slides of the first and second drive groups are rigidlycoupled to one another.
 17. Machine tool according to claim 16, whereinthe first guiding slides are rigidly coupled to one anothermechanically.
 18. Machine tool according to claim 11, wherein the secondguiding slides of the first and second drive groups are rigidly coupledto one another.
 19. Machine tool according to claim 18, wherein thesecond guiding slides are rigidly coupled to one another mechanically.20. Machine tool according to claim 17, wherein a linear drive isassociated with the guiding slides respectively mechanically coupled toone another.
 21. Machine tool according to claim 20, wherein the lineardrive is a spindle drive.
 22. Machine tool according to claim 11,wherein all guideways for the guiding slides are disposed on the sameside of the points of application.
 23. Machine tool according to claim11, wherein a measuring system which detects a relative position of thefirst guiding slides in relation to second guiding slides of the firstdrive group and the second drive group is provided.
 24. Machine toolaccording to claim 23, wherein the measuring system is disposed onconnecting struts of the first guiding slides and of the second guidingslides.
 25. Machine tool for machining a workpiece by a relativemovement between the workpiece and a tool, comprising a machine frame, acarrier disposed on the machine frame and having a first receiving meansfor the workpiece or the tool, a compound slide system disposed on themachine frame and having a slide element which carries a secondreceiving means for the tool or the workpiece, respectively, and can bemoved by the compound slide system in relation to the first receivingmeans in a fixed movement zone of a compound slide movement area in thedirection of two compound slide movement axes running transversely inrelation to one another and comprising a drive device for moving theslide element that is movable in relation to the first receiving means,which drive device acts on the slide element at least two spaced-apartpoints of application by four drive struts extending parallel to atleast two different directions, and with which drive device the at leasttwo points of application can be positioned by means of the four drivestruts, said drive struts being of invariant length and acting on theslide element, each of which struts being pivotally connected to arespective guiding slide, which is guided in a linearly movable mannertransversely in relation to the longitudinal direction of the drivestruts, and all guideways for the guiding slides being disposed closerto a reference plane than the points of application, the reference planeextending through a spindle axis and perpendicular to a slide movementaxis X.
 26. Machine tool according to claim 25, wherein the guidewaysfor the guiding slides are disposed near a reference plane, which runsthrough the spindle axis and perpendicularly in relation to the slidemovement axis X.
 27. Machine tool according to claim 25, wherein theguideways for all the guiding slides are disposed on the side of thepoints of application facing the spindle axis.